1 Obviously you are bypassing the kickbacks in the normal procurement system as well as shopping around . 

2 Besides which, the original one has chrome bumpers.

3 Cost overruns on the prototypes.

Scrapping the initial designs is always something to do as soon as possible. If one of those initial scouts gets eaten by the Guardian, I always try to tell myself that at least it makes it easier to get rid of the design. It helps...a little.

4 The cost of a unit is constant, after design, but as your tech level increases, older technology in that tree becomes cheaper. The Colony I ship was designed after you had made some tech advances that were relevant to the units included. Equipment also gets smaller as your tech level goes up. I think, late in the game, that it's even possible to put colony units on a small frame.

5 TheShaper is correct that tech shrinks ship components. 2% per tech level in the relevant field, IIRC. And Construction tech level affects overall hull space as well. Usually around the point where you tech Duralloy you can fit a colony base plus extended fuel tanks on a large hull and extend your colonization range, for example. But if you try it at the beginning you are well short of having enough space.

But what I believe our host was talking about is that you can create a new colony ship design (or scout, or whatever) on the very first turn before you start any research at all. And it will be cheaper than the default designs. Default scout is 10, I think, but an identical redesign costs 8 -- big savings in the early game.

6 Exactly so. This has nothing to do with the cost decline caused by rising technology. The image above was from before I began any research.

7 My only guess is that the initial ship designs cost as if you had level 0 in all technologies, whereas you actually have level 1 as soon as you start the game.

8 You might be right about that. It does make sense.